I got a kick out of "Worse yet, the expansion joint between the slabs had no backer rod or sealant."

I had this happen on a job. No sealant at all. We pointed it out, they fixed it. Then they sued the contractor for a new floor. Made me sick
Oh yea and how'd I find it? I followed the ant trail. Ants always find a way

I posted my response on the website, I believe it is 100% the installer's fault. They shortcutted their testing and verification of slab suitability requirements and installed a moisture sensitive floor on a completely unacceptable slab.

I respect your choice to not provide a quote to mitigate. I do quote jobs that need mitigation, perhaps it muddies my reputation, but I also teach classes to eliminate the need for mitigation, so I hope it evens out in the end.

You found the problem, you know the answer, maybe you should help the owner out by correcting the problem. Who else can she turn to?